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An on-chip interconnect is a critical shared resource that affects the performance-energy envelope of
an entire multicore system. This aspect has led to a plethora of proposals in recent years for
efficiently architecting the NoC substrate. However, most of these designs are agnostic to the actual
application requirements in that they attempt to optimize a generic set of objective functions such
as latency and throughput and/or energy/power. Since not all applications demand
similar resources from the underlying interconnection substrate, an alternative approach
to designing an NoC is to utilize multiple networks each of which is specialized for
common application requirements, and dynamically steer requests of each application to the network
that matches the application's requirements.

To this end, we start with a top-down approach by analyzing the intrinsic communication requirements
of several applications. Our key observation is that, although applications, in general, can be
classified as either network bandwidth sensitive or latency sensitive, not all bandwidth (latency)
sensitive applications are equally sensitive to bandwidth (latency). Following this, we propose a
novel set of metrics that can dynamically classify applications as either bandwidth or latency
sensitive to steer them into appropriate networks. We propose two separate heterogeneous networks in
the on-chip interconnection substrate, where one network is tailored to optimize for bandwidth
sensitive applications and the second network for latency sensitive applications. Within each
sub-network, we prioritize applications based on their criticality of network resource demand.
Simulations with nine different designs of a 64-core 2D mesh architecture demonstrate
that our heterogeneous network architecture is 5\%/3\% better in weighted/instruction throughput while consuming 47\% lower energy when compared to an iso-resource single network.

%can improve the
%weighted speedup by 34\% and instruction throughput by 24\% when compared to a %competitive design.
%Further, the proposed design, while being competitive in performance to an iso-resource single
%network, can consume 47\% lower energy.
%5\%/3\% better in weighted/instruction throughput while consuming
%47\% lower energy when compared to an iso-resource single network.

%(36 applications in total, drawn from SPEC 2006, SPLASH and commercial workloads).
%Doing so allows us to classify our
%application suite into nine finer categories based on their network demand.

%there are subtle differences in these two classes and hence, we propose a new methodology to
%characterize applications based on the width and height of their communication epochs. Such a
%characterization  results in nine finer levels of communication granularity and their %corresponding
%CDF that can be used for predicting the future communication pattern. These observations lead %us to
%propose two separate NoCs ....

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